bottom set on a scary board

[TurdFerguson]

I had a similar hand last night (also w/ 99 leading to bottom set) and the analysis was the same, for the reasons Payoff stated.

Plus, if your opponent has not flopped a flush or straight but instead has some sort of combo draw (e.g. Ac Qd) you then put the heat on her to make a big call, rather than you calling the minraise and sweating the turn.